feat(diagnostics): add bounded runtime capture CLI

[beruro]

Problem

Runtime investigations relied on ad-hoc shell commands and screenshots. There was no repository-owned way to discover the ORGII process tree, record a bounded memory session, attach phase markers, stop safely, or turn samples into reviewable artifacts.

Solution

Add a standalone developer CLI under tools/orgii-diagnostics:

• pnpm diag:process discovers the ORGII root and related processes without mutating them.
• pnpm diag:memory records bounded NDJSON samples, supports markers/status/stop/report, and emits JSON, CSV, and Markdown summaries.

The recorder has an explicit lifecycle, a single active-session owner, PID-start-token validation, default 15-second sampling, default 720-sample limit, per-sample process caps, three-error termination, and symmetric timer/watcher cleanup. It is inert until explicitly invoked and adds no App import, Tauri command, frontend subscription, background task, or wire change.

Potential risks

• macOS WebKit attribution depends on system metadata and can become partial when the OS denies visibility; Linux records the root tree without macOS WebKit attribution, and Windows is rejected explicitly.
• Reports contain process names, command lines, and memory metadata, so artifacts must be inspected before sharing.
• Very large user-selected sample limits can create large files and make report generation use more memory.
• Simultaneous competing recorders are protected by PID identity and exclusive session metadata but have not been stress-tested at high concurrency.
• Rollback is deletion of the tool directory and three package scripts; there is no application data or schema migration.

Performance guard

Verdict: pass. The tool is opt-in, has one recorder owner, bounded default samples/process details/output, incremental persistence, and symmetric timer/stop-watcher cleanup.

Verification

Validated after merging current develop (017fb9afa) into head 5ee1ad30c without conflicts:

• pnpm diag:test — PASS, 13/13 tests covering parsing, lifecycle/cleanup, process snapshots, redaction, and report generation.
• pnpm typecheck — PASS.
• git diff --cached --check before the merge commit — PASS.
• Packaged /Applications/ORG2.app process discovery — PASS against a live installed app root.
• Packaged memory recording — PASS, 4/4 samples, sample_limit_reached, complete attribution on every sample, no skipped PID, and JSON/CSV/Markdown artifacts generated.
• The packaged capture identified backend, WebKit GPU, WebKit network, WebKit renderer, and owned tool roles; peak role RSS values were present in the generated report.
• The temporary packaged app instance was stopped after capture. No user-visible UI change is included, so screenshots are not applicable.

Published GitHub CI on head 5ee1ad30c is fully green: Frontend typecheck/lint/test, Rust clippy, and AI attribution all passed.